Motor fuel



United States Patent MOTOR FUEL Richard L. Sawyer, Beacon, and Herbert E. Vermillion, Wappingers Falls, N.Y., assignors to Texaco Inc., a corporation of Delaware No Drawing. Filed Feb. 16, 1959, Ser. No. 793,271

24 Claims. (CI. 44-58) This invention relates to an improved motor fuel for internal combustion engines characterized by a plurality of improved properties. More particularly, it involves the discovery that the incorporation of specified amounts of a two-component additive in motor fuel results in the production of a superior fuel characterized by improved road octane, anti-rust and anti-stalling properties and several decided advantages in engine performance including reduced wear, improved valve performance and life, less preignition, reduced induction system deposits, better fuel economy and reduced spark plug fouling.

This application is a continuation-in-part of our copending applicaion Serial No. 427,660, filed May 4, 1954, now abandoned.

The use of an oxidized wax as a motor fuel additive has been known for many years (e.g., see US. 1,826,439). It has also been taught in US. 2,066,234 to incorporate small amounts of a light naphthene base lubricating oil in motor fuel to act as a gum flux and as an upper cylinder lubricant. Recently, considerable attention has been directed to gasoline additives which improve preignition and spark plug fouling in automobile engines. In general, these additives have been of the phosphate ester type. This invention involves the discovery of a combination of light distillate mineral lubricating (lube) oil and an oxidate selected from a specified group in specific proportions forms a gasoline additive which imparts a large number of improved properties to a gasoline motor fuel.

In accordance with this invention the superior motor fuel comprises a gasoline containing 0.2 to 1.0 weight percent of a light distillate mineral lubricating oil and 0.002 to 0.015 weight percent of a component which is either an ester-type oxidate derived from deoiled macrocystalline wax and having a Neutralization (Neut.) No. between 60 and 100, a Saponification (Sap) No. above 170, a Neut. No. to Sap. N0. ratio between 0.25 and 0.5 and an unsaponifiable content less than 40 percent, or an oxidate derived from a parafiinic lubricating oil and having a Neut. No. between 55 and 80, a Sap. No. between 100 and 200, and an unsaponifiable content less than about 55 percent.

The ester-type oxidate component of the fuel usually has a Neut. No. between 70 and 95, a Sap. No. between 210 and 250, a Neut. No. to Sap. No. ratio between 0.3 to 0.4 and an unsaponifiable content between 30 and 35 percent, and is obtained by air oxidation of a deoiled macrocrystalline wax of 25 to 30 carbon atoms containing less than percent oil and separated from a distillate lube oil fraction of SAE to 30 grade by dewaxing.

The paraffinic oil oxidate of this invention preferably has a Neut. No. between 60 and 70, a Sap. No. between 120 and 165, a viscosity less than 100 S.U.S. at 210 F., a Lovibond cell color rating of less than about 100, and is obtained by air oxidation of a refined parafiin base lubricating oil having a viscosity between 140 and 180 S.U.S. at 100 F., a pour point less than 5 F., a color rating of less than 10, and an aniline point between 215 and 225 F.

This invention also covers a novel gasoline additive comprising 95 to 99.8 weight percent light distillate mineral lube oil and 0.2 to 5.0 weight percent of a component 2,965,458 Patented Dec. 20, 1960 which is either an ester-type oxidate derived from a deoiled macrocrystalline wax and having a Neut. No. between 60 and 100, a Sap. No. above 170, a Neut. No. to Sap. No. ratio between 0.25 and 0.5 and an unsaponifiable content less than 40 percent, or an oxidate derived from a paraffinic lube oil and having a Neut. No. between 55 and 80, a Sap. No. between and 200 and an unsaponifiable content less than about 55 percent.

The two-component additive comprising light distillate lube oil and oxidate material of prescribed properties is usually employed in premium motor fuels having a high octane rating and comprising a major portion of catalytically cracked base stock. Catalytically reformed gasoline containing a high aromatic content often comprises a substantial portion of a premium fuel of this type. The additive is particularly effective in leaded gasolines which are particularly prone to cause spark plug fouling and preignition in present-day high compression engines. Several of the advantages of the additive-containing fuel of this invention are particularly noticeably in leaded fuels, namely, less preignition, reduced spark plug fouling and improved valve performance and life. Road octane improvement and fuel economy, which are surprising characteristics of the additive-containing motor fuel of this invention, are realized in approximately equal degree in both leaded and non-leaded motor fuels.

The light lube oil component may be a naphthene base distillate, a parafiin base distillate or mixtures thereof, but must have a low carbon residue and an SUS viscosity at 100 F. between 50 and 300. A distillate lube oil fraction of this type is obtained by vacuum distillation of a naphthene base or paraffin base lube oil at approximately 20 to 40 mm. pressure and subsequent acid treatment of the distillate. The lube oil component generally used has an SUS viscosity at 100 F. of about 100. If the light lube oil component of the addtiive mixture does not have a Conradson carbon content below 0.02 percent and a viscosity within the prescribed range, the resulting gasoline will cause excessive carbonaceous deposits in engines.

The lube oil component constitutes 0.2 to 1.0 weight percent of the finished gasoline of this invention. The preferred concentration of this component is in the range of 0.3 to 0.8 weight percent, with approximately 0.6 weight percent usually employed. The preferred 0.6 weight percent concentration of light lube oil is obtained by adding to gasoline about 0.5 percent by volume of a lube oil frcation having an SUS viscosity at 100 F. of about 100.

The ester'type wax oxidate component obtained by air oxidation of deoiled macrocrystalline wax is the product which is described in detail in the commonly assigned copending application, Serial No. 712,073, filed Jan. 30, 1958, now US. Patent No. 2,894,970, in the names of J. K. McKinley, R. F. Nelson and-G. S. Bright. The ester-type oxidate has a Neut. No. of 60 to 100, a Sap. No. above 170 and a Neut. No. to Sap. No. ratio between 0.25 and 0.5 and preferably between 0.3 and 0.4. The ester-type wax oxidate is obtained by air oxidation of a deoiled macrocrystalline wax containing less than 5 percent oil and 20 to 33 carbon atoms per molecule at a temperature between 300 and 350 F., a pressure below 25 p.s.i.a. and an air velocity of 1.5 to 6 feet per second, equivalent to an air feed rate of 8 to 35 cubic feet of air per pound of wax per hour.

An ester-type oxidate which has given superior results in the motor fuel of this invention has been prepared from a to 127 F. melting point semi-refined paraflin wax separated from a distillate oil of about SAE 20 grade and having about 25 to 30 carbon atoms per molecule. The 125 to 127 F. melting point wax, which contains about 0.2 to 0.4 percent oil is separated from the distillate oil by solvent dewaxing with a solvent such as a methylethyl ketone-toluene mixture. The conditions employed in the oxidation of this particularly effective oxidate are a temperature of about 330 F., atmospheric pressure, an air velocity of 3 feet per second, equivalent in plant operation to an air feed rate of about 12.5 cubic feet of air per pound of wax per hour, and the use of a potassium permanganate catalyst. This ester-type wax oxidate has a Neut. No. of about 80, a Sap. No. of about 220, a Neut. No. to Sap. No. ratio of about 0.38 and an unsaponifiable content of about 33 percent.

It is essential to the success of the two-component addirive-containing motor fuel of this invention that an ester-type wax oxidate derived by oxidation of a macrocrystalline wax and having a Neut. No. between 60 and 100, a Sap. No. above 170 and a Neut. No. to Sap. No. ratio below about 0.5 be employed. The improved performance characteristics which have been mentioned above are not obtained with acid-type oxidates from deoiled parafiin wax and ester-type oxidates from petroleum.

The paraffinic oil oxidate component obtained by catalytic air oxidation of a refined paraffin base lubricating oil is the product described in detail in the commonly assigned copending application Serial No. 710,856, filed January 24, 1958, in the names of George B. Kirkwood and John H. Greene. The paraffinic oil oxidate has a Neut. No. between 55 and 80, a Sap. No. between about 100 and 200, an unsaponifiable content less than about 55 percent, a viscosity less than 200 Saybolt Universal seconds (SUS) at 210 F., a color rating less than 200 in the Lovibond V2" cell, and a pour point less than 30 F. The preferred liquid oxidates of this invention have a Neut. No. between 60 and 70, a Sap. No. between 120 and 165, an unsaponifiable content less than 55 percent, a viscosity less than 100 SUS at 210' F., a Lovibond 1%" cell color rating of less than 100 and a pour point less than about 10 F.

The paraffin oil oxidate is obtained by reacting a refined paraffinic lubricating oil having a viscosity of between 90 and 350 SUS at 100 F., preferably between 140 and 180 SUS at 100 F., a pour point less than 10 F., preferably less than 5 F., a Lovibond A" cell color rating of less than 10 and an aniline point between 210-230 F., preferably between 215 and 225 F. with air in the presence of a metalliferous oxidation catalyst in a catalytic amount, e.g., between about 0.1 and 2 percent by weight of the charge oil, at an air feed rate of about 8-50 cu. ft./lb. oil/hr., at an air velocity of about 0.1 to 6 ft./sec. in an oxidation temperature range of about 250-400 F., and at a pressure of about 30-300 pounds per square inch gage (p.s.i.g.). The preferred conditions are an air feed rate of l-25 cu. ft./lb. oil/hr., an air velocity of about 0.2 to 1 ft./sec., an oxidation initiation temperature of 330-370 R, an oxidation reaction temperature of 260300 F., 50-90 ps.i.g. and potassium permanganate catalyst in an amount of about 0.4 to 1.2 percent by weight of the charge oil, more preferably in the range of about 1 to 1.2 percent. The oxidation is continued until the oil is oxidized to a Neutralization Number (Neut. No.) between about 55 and 80. preferably between 60 and 70. Approximately between 1-6 hours reaction time is necessary to arrive at a Neut. No. in the specified ran e.

When the oxidation step is completed, the liquid oxidate is rapidly cooled to below about 200 F. prior to removal from the reactor at a cooling rate of about to 50 F./minute, preferably between about 10 to F./minute. The oxidate is then withdrawn from the reactor and filtered to remove any solids contained therein.

The oxidate constitutes a very minor portion of the fuel composition of the invention, its concentration fallina within the range of 0.002 to 0.015 weight percent of the finished gasoline. The usual concentration of the oxidate material is in the neighborhood of 0.004 to 0.008 weight percent of the finished gasoline. Concentrations of oxidate in excess of 0.015 weight percent degrade the properties of the fuel particularly in the matter of the combustion chamber and intake system deposits. If the concentration is below the prescribed lower limit, the fuel does not show the improved performance characteristics.

From the foregoing description, it is apparent that the gasoline additive of this invention comprises to 99.8 weight percent of a light distillate lube oil and 0.2 to 5 weight percent of the oxidate material of prescribed properties derived either from macrocrystalline wax or parafiinic lubricating oil. The preferred concentration of oxidate in the additive is in the range of 0.5 to 2.0 weight percent. Although it is possible to prepare the improved motor fuel of the invention by separate addition of the light distillate oil and of the oxidate, it is customary to prepare the two-component additive and use it as a blending agent for the preparation of the additive-containing motor fuel.

An additive mixure containing the proper proportion of components is prepared, for example, by incorporating about 0.08-0.09 pound of paraffin oil oxidate in a gallon of naphthene base lube oil having an SUS viscosity at F. of about 100. The resulting additive contains approximately 1.125 percent oxidate. This additive is characterized by a Neut. No. of about 0.66, a pour point of 45 R, an SUS viscosity at 100 F. of and a gravity API of 22.9. The addition of about 0.5 percent by volume of this two-component additive in the motor fuel base stock gives a finished gasoline containing approximately 0.0075 weight percent oxidate and 0.6 percent naphthene base lube oil.

The superior performance of the improved motor fuel of the invention, wherein the ester-type wax oxidate was the additive component, has been demonstrated in laboratory bench tests and in high speed and low speed road tests. Laboratory bench tests were the type usually em ployed to evaluate the properties of motor fuels and will be described in more detail hereafter. A 25,000-mile road test was run at high speed-high temperature conditions, specifically, at 65 m.p.h. in two eight-hour shifts per day, in the San Antonio, Texas, area; this test was designed to evaluate the performance of the improved motor fuel under heavy duty conditions. A 7,000 mile road test was run under low speed-low temperature, stop and go driving conditions, specifically, at 35 mph. in three six-hour and 20-minute shifts per day in the Poughkeepsie, New York, area; this test was designed to evaluate the performance of the improved motor fuel under city driving conditions.

In the 25,000-mile road test, nine cars were run on the improved motor fuel of this invention, while nine cars were run on a reference fuel which consisted of a leaded fuel comprising mainly catalytically cracked gasoline and having a motor octane rating of about 95. A Buick, two Oldsmobiles, two De Sotos, two Chevrolets, a Ford and a Plymouth, all 1953 models except the De Sotos and the Plymouth, which were 1954 models, were run on the improved motor fuel, and nine cars of similar types and models were run on a reference fuel. In addition, three cars, specifically, a 1954 Oldsmobile, a 1954 De Soto and a 1953 Chevrolet, were run on the reference fuel containing 0.0283 weight percent trichloropropyl thionop osphate, and an additional three cars of the same types and models were run on a premium leaded motor fuel containing 0.033 weight percent tricresyl phosph"te. All of the cars were lubricated with a detergent-type motor oil of the heavy duty tvpe meeting Supplement I level requirements and of SAE grade 20.

In the low speed 7,000-mile test, four cars, s ecifically, a 1953 Old mobile, a 1953 Cadillac. a 1953 Chevrolet 75 and a 1954 De Soto, were run on the improved motor fuel of this invention, while four cars of s'imilar'types and models were run on reference fuel; two cars, specifically, a 1953 Oldsmobile and a 1954 De Soto, were run on reference fuel containing 0.0283 weight percent trichloropropyl thionophosphate, while two cars of similar types and models were run on a premium leaded base fuel containing 0.033 weight percent tricresyl phosphate. Advanced Custom Made Havoline, SAE 20 grade, was used to lubricate all of the cars in the low speed 7,000- mile test. Since this test was conducted in December- January in the northern part of the country, a permanent glycol-type antifreeze was used in the cooling system.

In both road tests, all engines were disassembled, all parts washed or sprayed with L-4-type cleaner, and the engines reassembled using the manufacturers specified clearances and tolerances with the exceptions which will be itemized below. All parts removed from the engines were checked visually for possible defects, and reinstalled in the engines in their original positions, unless defective.

Compression rings were weighed to the nearest milligram and gapped to the nearest 0.00025" before and after the test to determine wear. Rings were cleaned with L-4-type cleaning solution and polished with metal polish before measurements were taken.

Cylinder bores were measured to the nearest 0.00025" at the center of the top ring at top and bottom stroke perpendicular and parallel to the crank shaft on all cylinders before and after test.

All con'rod bearing inserts were weighed to the nearest milligram before and after test to determine weight loss. All bearings were returned to their original positions.

Air cleaners were disassembled, thoroughly cleaned with solvent and reassembled after oiling the element or filling with new oil (if oil bath-type) of the kind used in the engine crankcase.

All cars in the 25,000-mile test were equipped with 180 F. thermostats. All cars in the 7,000-mile test were equipped with 150 F. thermostats.

All cars in the 25,000-mile road test were given a 900-mile break in. There was no necessary of a break-in in the 7,000-mile road test since speed did not exceed 35 mph.

The reference fuel employed in both road tests and in the laboratory evaluation of the motor fuel additive of this invention was a high quality premium grade fuel comprising mainly fluid catalytically cracked stock and straight run gasoline. The reference fuel had a 95 ASTM research octane rating, contained 2.74 ml. of TEL fluid per gallon, had a API gravity of 60 to 65 and a boiling point range between 100 and 398 F.; the base fuel was negative in the copper corrosion test and had an oxidation stability in the ASTM test of 240 minutes minimum. The reference fuel also contained minor amounts of conventional gasoline inhibitors, for example, approximately 6 pounds of N-N' -diseco-ndary butyl-p-phenylenediamine, a gum inhibitor, per thousand barrels of gasoline, about 1.2 pounds of N-N' -disalicylidene-l. Z-diaminopropane, a metal deactivator, per thousand barrels of gasoline, and about 1.1 pounds of lecithin, a tetracthyl lead stabilizer, per thousand barrels of gasoline.

The improved motor fuel used in these road tests was made by incorporating in the above reference fuel 0.5 percent by volume of a two-component additive comprising 0.057 pound of ester-type wax oxidate derived by catalytic oxidation of macrocrystalline wax isolated from a lube oil distillate of SAE 20 grade and having a Neut. No. of 80, a Sap. No. of 230 and an unsaponifiable content of 33 percent in a gallon of naphthene base lube oil having an SUS viscosity at 100 F. of about 100. The finished gasoline contained approximately 0.005 weight percent ester-type oxidate and about 0.6 weight percent naphthene base lube oil.

, The trichloropropyl thionophosphatecontaining fuel was prepared by incorporating 0.0283 weight percent of the agent in the above-described reference fuel.

The tricresyl phosphate-containing test fuel was a purchased premium grade motor fuel of a major integrated petroleum corporation.

RING WEAR After completion of the 25,000-mile and 7,000-mile road tests, the compression rings were weighed to the nearest milligram after cleaning with L-4-type cleaning solution and polishing with metal polish. Ring wear was determined by the weight loss of the rings during the road test. In Table I, there is shown the average weight loss of compression rings per car in the 25,000- mile road test with the various fuels used therein.

Table I 25,000-MILE ROAD TEST Average weight loss in mgs. compression rings per car Reference fuel 410 Reference fuel containing naphthene base oil-wax oxidate additive 265 Reference fuel plus trichloropropyl thionophosphate 263 Tricresyl phosphate-containing premium fuel 316 The conditions in the 7,000-mile road test were not sufliciently severe for significant differences in ring wear to be observed.

EXHAUST VALVE PERFORMANCE AND LIFE In the 25,000-mile high speed road test, a total of 26 exhaust valve failures was obtained on the nine cars utilizing the reference fuel. In sharp contrast, in the nine cars employing the additive-containing motor fuel of this invention, only eleven exhaust valve failures resulted in the high speed tests. In the three cars employing the tricresyl phosphate-containing motor fuel, six exhaust valve failures were obtained in the high speed road test; in the three cars running on the reference fuel containing trichloropropyl thionophosphate, five exhaust valve failures were encountered. The clear superiority of the motor fuel of this invention over the reference fuel and over different types of motor fuel additives is apparent in the field of exhaust valve life.

There were no exhaust valve failures with any of the fuels in the 7,000-mile test, as would be expected from the mild operating conditions employed in this test.

Evaluation of the exhaust valves by a merit rating system similar to the CRC L-4-545 Test used for evaluating pistons and described in detail on page 401 of the CRC handbook, 1946 edition, under the heading Oxidation Characteristics of Heavy Duty Motor Oils," showed a substantial improvement for the improved motor fuel of this invention in both the 25,000-mile and 7,000-mile road tests. This merit system involves visual examination of the engine part in question, exhaust 'valves in this instance, and rating them according to deposits by comparison with standards which have been assigned ratings; a rating of 10 is optimum, and a rating of 0 represents the worst condition. Table II shows the average exhaust valve merit ratings of valves from all cars testing fuels containing all four additives after completion of the 25,000-mile and 7,000-mile road tests.

Table II EXHAUST VALVE MERIT RATING VALVE 7 ANTI-STALLING PROPERTIES The anti-stalling properties of the improved fuel of this invention were demonstrated in a laboratory cold room equipped with temperature and humidity controls. The procedure employed was similar to that described in column 3 of U.S. 2,579,692, and briefly involved the determination of the stalling characteristics of the car during the warm-up period while the temperature and humidity were maintained at particular levels. The procedure employed was to start the car and immediately raise the engine speed to 1,500 r.p.m., which speed was maintained for 30 seconds, and then allow the engine to idle for 15 seconds; if the engine stalled before 15 seconds had expired, the car was again started and raised to a speed of 1,500 r.p.m. for 30 seconds; if stalling did not occur, the speed was immediately increased to 1,500 r.p.m. after the 15-second idling time. The alternate cycles of 30 seconds at 1,500 r.p.m. followed by 15 seconds of idling were repeated until the engine was completely warmed up. The number of stalls encountered up to the time of complete engine warm-up was recorded. The tests were recorded at 40 F. and at a relative humidity of 90 to 95 percent.

With the reference fuel under these conditions, 8 stalls per warm-up were encountered, while with the additive-containing fuel, only 7 stalls per warm-up were encountered, an improvement of about 16 percent. This 16 percent improvement is significant since the reference fuel, itself, is considered to possess excellent anti-stalling properties.

FUEL ECONOMY The average mileage obtained with the 9 cars in the high speed road test was 16.6 miles per gallon with the reference fuel and 16.9 miles per gallon with the fuel containing the naphthene base oil-ester-type wax oxidate additive. In the 7,000-mile road test conducted under conditions simulating city driving, the average mileage with the 4 cars with the reference fuel was 15.4 miles per gallon; with the additive-containing fuel, the average mileage was 16.2 miles per gallon. These results are significant, particularly in light of the extensive nature of the two road tests and the variety of cars employed therein. The increase in mileage obtained with the additive-containing fuel of this invention in the 7,000- mile road test is better than a percent increase in mileage.

The superior fuel economy obtainable with the additivecontaining fuel of this invention in comparison with the reference fuel was further substantiated by the results obtained on two of the 1953 Chevrolets employed in the 25,000-mile road test. The Chevrolets, one of which had been run on the reference fuel and the other on the naphthene base oil-ester-type wax oxidate additive-containing fuel, were continued on the road test on the same fuels to 50,000 miles. The average mileages obtained during the 25,000 additional miles of road test were 15.04 miles per gallon on the Chevrolet using the reference fuel and 16.74 miles per gallon on the Chevrolet using the additive-containing fuel of this invention. It appears that the improvement in fuel economy employing the additive-containing fuel of this invention becomes even more pronounced as the engines accumulate more mileage.

It has been theorized that the improved valve seat condition obtainable using the additive-containing fuel of this invention is a factor in the improved mileage obtained therewith. With improved valve seat conditions, high compression ratios are maintained with a resulting improvement in fuel economy.

ROAD OCTANE The road octanes of the reference fuel and the addi five-containing fuel were determined by the Modified Uniontown method, which is designated CRC-F-28, and which is described in Road Rating Techniques, CRC, January 16, 1951. Appendix A. The Modified Uniontown method involves determining road octane under cons ditions of acceleration rather than at steady speeds on a steep grade.

Table III compares road octanes of the additive-com taining fuel and of the reference fuel.

Table III ROAD OCTANE RATINGS IN 1953 CARS Reference Fuel+ Car Make Reference Fuel Naphthene Base Oil-Wax oxidate Additive Cadillac-. 91. 2 93.1 Pontiac- 92. 6 93. 7 Dod e. 91. 5 92. 5 Buick 90. 9 92. 5

ANTICORROSIVE PROPERTIES The reference fuel and the additive-containing fuel were compared in the so-called Quickie" corrosion test, which is performed as follows: A A" x 5" 16-gauge iron strip which has been cleaned by contact with dilute HC] solution, water washing, drying with acetone and air, and has been polished with an emery cloth, is immersed in 110 cc. of oil to be tested in a 4ounce bottle. After the strip has been immersed in the oil for 5 minutes, 20 cc. of oil is removed from the 4-ounce bottle and replaced with 20 cc. of distilled water. The bottle is then shaken for 15 minutes in a horizontal position after which it is turned upright on a flat surface. After standing for 3 hours, corrosion readings on the portion of the strip immersed in the oil phase are determined by use of a comparator and are expressed in percent rust on the strip in the oil phase.

With the reference fuel, 20 percent of the area immersed in the oil phase was corroded. In contrast, with the additive-containing fuel, only 1 percent of the oilimmersed area was corroded. The presence of the distillate oil-wax oxidate in the premium leaded gasoline effected a 20-fold increase in anticorrosive properties of the fuel.

INTAKE SYSTEM AND SPARK PLUG CLEANLINESS The intake system cleanliness and spark plug cleanliness were evaluated by the merit rating system employed for evaluation of the exhaust valves and based on the CRL-L-4-545 method of rating piston condition. The deposits were assigned ratings of 0 to 10, with 0 representing the worst condition and 10 the optimum condition with respect to deposits. The average ratings of the intake manifo ds, intake ports and spark plugs of cars run on all four fuels after completion of the 7.000-mile and 25,000-mile road tests are shown in Table IV.

The superiority of the additive-containing fuel of this invention over the reference fuel and over fuel containing competitive additives is clearly demonstrated in the foregoing table in the matter of intake system and spark plug cleanliness. The fuel containing chloropropyl thionophosphate is particularly poor in intake system and spark plug cleanliness.

OCTANE REQUIREMENT INCREASE Octane requirement increase is a characteristic of the modern high compression engine. An engine which has an initial octane requirement of often will develop a 9 Table IV ROAD EVALUATION OF INTAKE SYSTEM AND SPARK PLUG CLEANLINESS Intake Intake Spark Intake Intake Spark Manf- Port Plug Mani- Port Plug fold fold Reference fuel 8. 5 9. 8 8. 8 8. 5 6. 9 6. 3 Reference fuel eontalningnaphthene base oil Wax oxfdate addltive. 10.0 9.8 9.0 9.3 7.6 7.4 Reference fuel+ ohloropropyl thlonophosphate. 8. 8 9. 9 B. 5 B. 7 5. 3. 8 'Irlcresyl phosphate-containlng premium fuel"-.. 9. 9. 4 7. 9 8. 9 6. 1 6. 2

need for a 95 octane fuel during service. It has been postulated that octane requirement increase is attributable partially to engine design and partially to the fuel.

Reduced octane requirement increase as derronstrated in the laboratory for the additive-containing motor fuel of this invention in comparison with the reference fuel by a procedure involving a determination of the initial octane requirement using selected leaded primary reference fuels. In the determination of the initial octane requirement increase, the engine is accelerated at wide open throttle at 700 to 2,000 rpm. with a dynamometer preloaded so that the acceleration consumes approximately 12 seconds. The quality of the reference fuel is continually lowered until engine knock is just audible. The octane number of the fuel used when engine knock is, just audible is the octane requirement of the engine. After three hours of operation, the accelerations are repeated with a reference fuel two numbers above the initial octane number requirement. Four accelerations with reference fuel are made, and if knock occurs on at least two, it is recorded as an octane requirement increase. If knock only occurs on one acceleration or not at all, the same reference fuel is used at the end of the next three hours; if knock still does not occur on at least two ac celerations, the reference fuel two octane numbers lower is used at the end of the succeeding three hours. When knock occurs on at least two accelerations, it is counted and the reference fuel two octane numbers higher is used at the end of the succeeding three hours. After the engine has reached an octane requirement of 96, the reference fuels are used in one octane number increments after each three hours of operation. The conditions for both the octane requirement increase and preignition tests are as follows:

In a laboratory test, the additive-containing fuel of this invention gave an octane requirement increase of 10.3 units in the above test, Whereas the reference fuel gave an octane requirement increase of 11 units.

PREIGNITION Preignition is determined in conjunction with the foregoing octane requirement increasc test, and is characterized by engine run-on, that is, operation without normal spark ignition, when combustion knock occurs during the The preignition rating is equal" full throttle acceleration. to the ratio of the occurrence of run-on to the number T0 of times combustion knock is encountered during a run, that is,

No. of run-onX 00 W The ratings of the various fuels in the preignition tests are shown in Table V.

preignition rating= Table V PREIGNITION RATING Percent preignition Reference fuel 70 Reference fuel containing naphthene base oil-wax oxidate additive 20 Reference fuel plus trichloropropyl thionophosphate 16 The foregoing data show the clear superiority of the additive-containing fuel of this invention over the reference fuel. It is noteworthy that the trichloropropyl tihonophosphate-containing fuel is approximately equivalent to the additive-containing fuel of this invention in improving preignition.

The foregoing road tests and laboratory data conc1usively demonstrate the improved performance obtained using the additive-containing motor fuel of this invention in a large number of different cars. The improved performance characteristics obtained with the motor fuel containing a light distillate oil and an ester-type oxidate derived from deoiled parafiin macrocrystalline wax are summarized as follows:

(1) Reduced wear.

.(2) Improved valve performance and life.

(3) Rust protection.

(4) Reduced spark plug fouling.

(5) Reduced'induction system deposits.

(6) Improved anti-stalling properties.

(7) Improved preignition characteristics.

(8) Higher road octane.

(9) Reduced octane requirement increase.

Although the road test was run employing a light naphthcne base distillate as a component of the additive, laboratory data have indicated that a mixture of estertype Wax oxidate and light paraffin base distillate having an SUS viscosity at 100 F. between 50 and 300 performs excellently as a motor fuel additive. An additive-containing motor fuel Was prepared by incorporating in the afore-describcd reference fuel 0.5 percent by volume of a Z-component mixture made by adding 0.057 pound of ester-type wax oxidate used in the road test to a gallon of paraffin base distillate lube oil having an SUS viscosity at 100 F. of about 105. The finished gasoline contained approximately 0.005 weight percent ester-type oxidate' and about 0.6 weight percent paraffin base distillate oil. Another motor fuel was prepared by incorporating in the same reference fuel a 2-component additive made by* adding 0.057 pound of ester-type Wax oxidate to a white oil obtained by exhaustive refining of a naphthene base distillate oil by H treating and having an SUS viscosity at F. of 100. The 2 fuels were compared with the naphthene basc-ester-type oxidate-containing fuel employed in the road tests in the laboratory in the Chevrolet CRC FL-2 test. In Table VI, there are shown the merit ratings of these fuels using the previously-described CRC L4-545 rating system.

Table VI '11 The foregoing data show that a paraflin base distillate and a highly refined distillate which has been sulfuric acid treated may be substituted for naphthene base distillate oil in the Z-component additive mixture of this invention.

The foregoing test data showing the superiority of fuel composition containing the additive of the invention wherein the ester-type wax oxidate was a component are common to this specification and that of application Ser. No. 427,660, filed May 4, 1954, and of which this application is a continuation-in-part.

The superior performance of the improved motor fuel of the invention wherein the paraflinic lubricating oil oxidate was the additive component, has also been demonstrated in laboratory bench tests and in high speed road tests. In these tests the data obtained indicated that fuels containing the additive with the paraffinic oil oxidate component were at least equivalent in performance to fuels containing the additive with the estertype wax oxidate component.

The road test conducted to evaluate the paraflinic oil oxidate containing additive consisted of four round-trip runs over the same road course daily in the San Antonio, Texas, area for an accumulation of 750 miles per day and a total mileage of 20,000 miles. Maximum speeds were limited in accordance with legal regulations and good judgment. Speed limits of 60 mph. during the day and 55 mph at night prevailed on the open road and various limits as low as 30 mph. were maintained in towns along the test route.

In this road test, four 1957 Buick Series 40 (Special) with Dynaflow were used in connection with the testing of the motor fuels of this invention. Two of the cars were run on the base fuel plus the 0.5 wt. percent paraffinic oil oxidate-containing additive and the other two cars were run on the base fuel plus 0.5 wt. percent estertype wax oxdate-containing additive for comparison since the excellent performance of this fuel had been well established by extensive road testing and years of customer satisfaction. All four cars used detergent-type motor oil of the heavy duty type meeting Supplement I level requirements and having an SAE grade of -20W.

Extensive preparations prior to the actual road testing were made in much the same manner as the preparations, including engine adjustments and inspections, previously made in connection with the road testing of the motor fuel containing the ester-type wax oxidate-lube oil additive of the invention and reported earlier in this specification.

The base fuel comprised mainly light fluid catalytically cracked stock and catalytically reformed gasoline. This base fuel had an ASTM research octane rating of 99, contained 2.82 cc. of tetraethyl lead fluid per gallon, had a API gravity of 56.6 and a boiling range between 98 and 366 F. This base fuel also contained minor amounts of conventional additives. These additives included about 1.2 lbs. per 1000 bbl. of N,N'-disalicylidene- 1,2-diaminopropane, a metal deactivator, and about 6 lbs. per 1000 bbl. of N,N-disecondary butyl-pphenylenediamine, a gum inhibitor.

The motor fuel containing the ester-type wax oxidate component additive was obtained by adding to the base fuel 0.5 percent by volume of the additive comprising 0.8 volume percent of ester-type wax oxidate derived by catalytic oxidation of macrocrystalline wax isolated from a lube distillate of SAE 20 grade and having a Neut. No. of 80, a Sap. No. of 230 and an unsaponifiable content of 33 percent, in a naphthene base lube oil having an SUS viscosity of 100 F. of about 100. This fuel composition, which will hereinafter be referred to as motor fuel containing additive A, contained 0.005 wt. percent ester-type wax oxidate and about 0.6 weight percent naphthene base lube oil.

The motor fuel containing the paraffinic oil oxidate component additive was prepared by adding to the base fuel 0.5 percent by volume of an additive comprising the same lubricating oil component used in additive A and about 1.125 volume percent of an oxidate prepared by catalytic oxidation of a refined paraflin base lube oil having an SUS viscosity at F. of 144, a API gravity of 31.8 and a pour point of --5' F. This fuel composition, which will hereinafter be referred to as motor fuel containing additive B, contained 0.0075 wt. percent parafiin oil oxidate and about 0.6 weight percent naphthene base lube oil.

RING WEAR After completion of the 20,000 mile road test, the compression rings were weighed to the nearest milligram after cleaning with L-4 type cleaning solution and polishing with metal polish. Ring wear was determined by the weight loss of the rings during the road test. In Table VII there is shown the average weight loss of compression rings per car in the 20,000 mile road test with the two specified fuel compositions of the invention.

Table VII COMPRESSION RING WEAR Avg. wt. loss in mg. Base fuel+additive A 180 Base fuel+additive B This demonstrates that the parafiin oil oxidate-lube oil additive compares very favorably with the excellent wax oxidate-naphthene oil additive of the invention in respect to ring wear.

EXHAUST VALVE PERFORMANCE Evaluation of the exhaust valves by a merit rating system similar to the CRC L-4-545 Test used for evaluating pistons and described in detail on page 401 of the CRC Handbook, 1946 edition, under the heading "Oxidation Characteristics of Heavy Duty Motor Oils," showed a substantial improvement for the improved motor fuel of this invention in the 20,000 mile road test. This merit system involves visual examination of the engine part in question, exhaust valves in this instance, and rating them according to deposits by comparison with standards which have been assigned ratings; a rating of 10 is optimum, and a rating of 0 represents the worst condition. Table II shows the average exhaust valve merit ratings of valves from all cars testing fuels containing all four additives after completion of the 20,000 mile road test.

Table VIII EXHAUST VALVE MERIT RATING Avg. Ex. Avg. Ex. Tulip Stem Base tuel-l-Addltlvs A 7. 2 T. Base Iuel-t-Additlve B 7. 2 7. 3

Additive B (oil oxidate+oil) compares very favorably with the excellent additive A (wax oxidate-l-oil) with respect to exhaust valve cleanliness as seen in the above table.

FUEL AND LUBRICANT ECONOMY The average mileage obtained for both fuel and oil for the test cars in the 20,000 mile road test is set forth in the following table:

13 In this aspect of automotive performance the motor fuel containing additive B again ranks in the class of the superior additive A.

INTAKE SYSTEM AND SPARK PLUG CLEANLINESS Table X INTAKE SYSTEM AND SPARK IGNITION CLEANLINESS Spark Plugs Intake Intake Manifold Ports Deposits Erosion Base tuel+Additivc A. 9 7 8 9 Base tuel+Additive B 9 8 7. 8. 5

Both additive containing fuels of this invention demonstrate excellent cleanliness properties in the intake system and on the plugs of the test cars.

The motor fuel compositions of this invention were also investigated in well known laboratory bench tests. In the following bench tests the base fuel used was very similar to the road test fuel and comprised a high grade premium fuel consisting mainly of fluid catalytically cracked gasoline and catalytically reformed gasoline having a API gravity of 60.1, an ASTM research octane number of 98.0 with 2.89 ml. per gal. of tetraethyi lead fluid, and a boiling range of from 110 to 362 F. The base fuel also contained 1.2 lbs. per 1000 bbl. of the metal deactivator N,N-disalicylidene-l,Z-diaminopropane, and 6 lbs. per 1000 bbl. of a gum inhibitor, N,N'- disecondary butyl-p-phenylene diamine. As in the road tests, this base fuel was used with 0.5 volume percent of additive B (oil oxidate lube oil) proportioned so that 18 lbs. of oxidate are present in 1000 bbl. of the base fuel.

LOW TEMPERATURE DEPOSITS The laboratory Chevrolet-CRC-FL-2-545 Test procedure was used to evaluate the low temperature deposit forming characteristics of a fuel containing the paraffin oil oxidate-lube oil additive B of the invention. As previously stated, the merit system used to rate the engine parts in this test involves visual examination of the part in question and rating them according to deposit formation by comparison with standards which have assigned ratings; a rating of 10 is optimum, and a rating of 0 represents the worst possible condition.

The following table gives the results obtained in the testing of the fuels:

Table XI ENGINE CLEANLINESS Engine Parts Base Fuel Base Fuel-i- Addltive B 0 lps s ms s sm CHUGOOQOOUI r s w r s \JDUQCGOON 14 These data indicate that the base fuel, a high grade, exceptionally clean burning fuel, is not degraded by the addition of the additive of the invention since both fuels tested are equivalent with respect to low temperature deposits as evaluated in this test.

OCTANE REQUIREMENT INCREASE As previously related octane requirement increase (ORI) is a characteristic of modern high compression engines. An engine which has a given initial octane requirement often will develop a need for a higher octane fuel during this service. The composition of the fuel used in the engine will generally effect the extent of ORI. The laboratory test procedure used in developing the ORI of an engine using a fuel composition containing the paraffin oil oxidate-lube oil additive B of this invention has previously been described in connection with the evaluation of a fuel containing the ester-type wax oxidate-lube oi] additive A of this invention. Briefly the test procedure involves running a single cylinder Lauson engine under conditions designed to develop the ORI of the engine utilizing a specified fuel, which results will be indicative of the relative performance of the fuel with respect to ORI under actual driving conditions.

The following table shows the results of the testing of additive B in the base fuel as to octane requirement increase and engine cleanliness under the test conditions. Engine parts are rated for cleanliness as in the foregoing CRC-FL-2-545 Test procedure.

Table XII OCTANE REQUIREMENT INCREASE AND ENGINE CLEANLINESS Base Fuel Base fuella Add.

It is demonstrated in the above table that the paraffin oil oxidate-lube oil additive of the invention improves ORI and is either equivalent to or surpasses the high grade base fuel in cleanliness properties in this test procedure.

SURFACE IGNITION The problem of surface ignition has become emphasized as engine designs change to provide more effi cient utilization of fuels. Surface ignition can be subdivided into preignition, which is surface ignition before the occurrence of normal spark, and post ignition, which is surface ignition that occurs after passage of the normal spark. The effect of surface ignition on engine performance is resultant loss of power, inefficient utilization of fuel, and knock in certain cases. The role of petroleum products with regard to the surface ignition problem involves: i) the formation of combustion chamber deposits which are potential hot spots and will ignite the charge independently of normal ignition, and (2) the relative tendencies of fuels to be ignited by these glowing deposits.

The apparatus and procedure for evaluation of surface ignition tendencies for fuels was reported in Deposit- Induced Ignition," SAE Transactions, vol. 62, 1954, pp.

40-49. A CFR-L head engine was used in conjunction The ionization gap is mounted in a port at the center of the cylinder head. Flame fronts passing through the gap provide a conducting path for the voltage impressed on the two electrodes. The resulting signal activates a recording counter. Differentiation between normal and abnormal flame fronts is accomplished by making the counter operate only during a selected portion of the engine cycle. The test engine cycling schedule differed slightly from that reported in the reference.

Table XIII SURFACE IGNITION TEST Surface ignition counts/hr. Base fuel 330 Base fuel-i-additive B 285 These data indicate that the additive containing fuel is at least equivalent to the base fuel with regard to surface ignition tendencies.

ANTI-CORROSIVE PROPERTIES In the Quickie corrosion test as previously described in connection with the evaluation of a fuel containing the ester-type was oxidate-lube oil additive, the metal strip immersed in the base fuel showed 25 percent rust after 3 hours whereas the strip immersed in the base fuel plus the parafiin oil oxidate at 18 lbs. per 1000 bbl. of fuel showed only 3 percent rust after 3 hours. This shows a reduction in rusting tendency of over 8 times that of the base fuel.

The parafiin oil oxidate-lube oil additive and the estertype wax oxidate-lube oil additive of this invention have convincingly shown in the foregoing extensive bench and road testing that they lend many very superior qualities to motor fuels and that they are unexpectedly excellent additions to the motor fuel art.

Obviously, many modifications and variations of the invention, as hereinbefore set forth, may be made without departing from the spirit and scope thereof, and therefore only such limitations should be imposed as are indicated in the appended claims.

We claim:

1. A motor fuel additive comprising from 95 to 99.8 weight percent light distillate mineral lubricating oil fraction having an SUS viscosity at 100 F. between 50 and 300 and a Conradson carbon content below 0.02 percent, and 0.2 to weight percent of an oxidate material selected from the group consisting of an oxidate derived from a deoiled macrocrystalline wax and having a Neut. N0. between 60 and 100, a Sap. No. above 170, a Neut. No. to Sap. No. ratio between 0.25 and 0.5 and an unsaponifiable content less than 40 percent, and an oxidate derived from a parafiinic lubricating oil and hav ing a Neut. No. between 55 and 80, a Sap. No. between 100 and 200, an SUS viscosity at 210 F. less than 200, a Lovibond A" cell color rating less than 200, and an unsaponifiable content less than about 55 percent.

2. A motor fuel additive as described in claim 1 wherein said oxidate material is the oxidate derived from a deoiled macrocrystalline wax and having a Neut. No. between 60 and 100, a Sap. No. above 170, a Neut. No. to Sap No. ratio between 0.25 and 0.5 and an unsaponifiable content less than 40 percent and the concentration of said oxidate is between 0.5 and 2.0 weight percent.

3. A motor fuel additive as described in claim 1 wherein said oxidate material is the oxidate derived from a paraflinic lubricating oil and having a Neut. No. between 55 and 80, a Sap. No. between 100 and 200, an unsaponifiable content less than about 55 percent and the concentration of said oxidate is between 0.5 and 2.0 weight percent.

4. A motor fuel additive as described in claim 1 in which said distillate lubricating oil fraction has an SUS viscosity at 100 F. in the neighborhood of 100.

5. A motor fuel additive comprising 95 to 99.8 weight percent light distillate mineral lubricating oil fraction having an SUS viscosity at 100 F. between 50 and 300 and a Conradson carbon content below 0.02 percent, and 0.2 to 5 weight percent of an oxidate derived from a deoiled macrocrystalline wax and having a Neut. No. between 70 and 95, a Sap. No. between 210 and 250, a Neut. No. to Sap No. ratio between 0.3 and 0.4, and an unsaponifiable content between 30 and 35 percent.

6. A motor fuel additive as described in claim 5 in which the oxidate is derived by air oxidation of a macrocrystalline wax having 20 to 33 carbon atoms, an oil content less than 5 percent and isolated by solvent dewaxing a parafiin base distillate oil.

7. A motor fuel additive as described in claim 5 in which the mineral lubricating oil fraction is a naphthene base oil having an SUS viscosity at 100 F. of about 100 and a Conradson carbon content below 0.02 percent, and the oxidate is obtained by air oxidation of 125 to 127 F. melting point semi-refined macrocrystalline wax and has a Neut. No. of about 80, a Sap. No. of about 220, a Neut. No. to Sap No. ratio of about 0.38, and an unsaponifiable content of about 33 percent.

8. A motor fuel additive comprising to 99.8 weight percent light distillate mineral lubricating oil fraction having an SUS viscosity at F. between 50 and 300 and a Conradson carbon content below 0.02 percent, and an oxidate derived from a parafiinic lubricating oil and having a Neut. No. between 60 and 70, a Sap. No. between and 165, an SUS viscosity at 210 F. less than 100, a Lovibond A" cell color rating less than 100, and an unsaponifiable content less than about 55 percent.

9. A motor fuel additive as described in claim 8 wherein the oxidate is derived by air oxidation of a refined paraflin base lubricating oil having an SUS viscosity at 100 F. between 90 and 350, and a pour point less than 10 F.

10. A motor fuel additive as described in claim 8 in which the mineral lubricating oil fraction is a naphthene base oil having an SUS viscosity at 100 F. of about 100 and a Conradson carbon content below 0.02 percent and the oxidate is derived by catalytic air oxidation of a refined paraffinic lubricating oil having an SUS viscosity at 100 F. of between and 180, and a pour point less than 5 F.

11. An improved gasoline containing 0.2 to 1 weight percent of a light distillate mineral lubricating oil fraction having an SUS viscosity at 100 F. between 50 and 300, and 0.002 to 0.015 weight percent of an oxidate material selected from the group consisting of an oxidate derived from a deoiled macrocrystalline wax and having a Neut. No. between 60 and 100, a Sap. No. above 170, a Neut. No. to Sap. No. ratio between 0.25 and 0.5 and an unsaponifiable content less than 40 percent and an oxidate derived from a paraflinic lubricating oil and having a Neut. No. between 55 and 80, a Sap. No. between 100 and 200, an SUS viscosity at 210 F. less than 200, a Lovibond /2" cell color rating less than 200, and an unsaponifiable content less than 55 percent.

12. A gasoline as described in claim 11 in which the concentration of said oxidate material is between 0.004 and 0.008 weight percent.

13. A gasoline as described in claim 11 in which the concentration of the mineral lubricating oil fraction is between 0.3 and 0.8 weight percent.

14. A gasoline as described in claim 11 in which said mineral lubricating oil fraction has an SUS viscosity at 100 F. in the neighborhood of 100 and a Conradson carbon content less than 0.02 percent.

15. A gasoline as described in claim 11 in which said oxidate material is an ester-type oxidate derived from deoiled macrocrystalline wax having a Neut. No. between 70 and 95, a Sap. No. between 210 and 250, a Neut. No. to Sap. No. ratio between 0.3 and 0.4 and an unsaponifiable content between 30 and 35 percent.

16. A gasoline as described in claim 11 in which said oxidate material is an ester-type oxidate derived by air oxidation of a macrocrystalline wax having from 20 to 33 carbon atoms, an oil content less than percent and isolated by solvent dewaxing paraflin base distillate oil.

17. A gasoline as described in claim 11 in which the mineral lubricating oil fraction is a naphthene base oil having an SUS viscosity at 100 F. of about 100 and a Conradson carbon content of less than 0.02 percent, and the oxidate material is an ester-type wax oxidate derived by air oxidation of 125 to 127 F. melting point semirefined macrocrystalline wax and has a Neut. No. of about 80, a Sap. No. of about 220, a Neut. No. to Sap. N0. ratio of about 0.38 and an unsaponifiable content of about 33 percent.

18. A gasoline as described in claim 11 in which the oxidate material is an oxidate derived from a parafiinic lubricating oil and having a Neut. No. between 55 and 80, a Sap. No. between 100 and 200 and an unsaponifiable content less than about 55 percent.

19. A gasoline as described in claim 11 in which the oxidate material is an oxidate derived from a paraifinic lubricating oil and having a Neut. No. between 60 and 70, a Sap. N0. between 120 and 165, and an unsaponifiable content less than about 55 percent.

20. A gasoline as described in claim 11 in which the mineral lubricating oil fraction is a naphthene base oil having an SUS viscosity at 100 F. of about 100 and a Conradson carbon content less than 0.02 percent and the oxidate material is an oxidate derived by air oxidation of a refined parafiin base lubricating oil having an SUS viscosity at 100 F. between 90 and 350 and a pour point less than F.

21. A gasoline as described in claim 20 in which the parafiinic lubricating oil has an SUS viscosity at 100 F. of between 140 and 180 and a pour point less than 5 F.

22. An improved leaded gasoline containing 0.3 to 0.8

weight percent of a light distillate mineral lubricating oil fraction having an SUS viscosity at 100 F. between and 300 and a Conradscn carbon content less than 0.02 percent and 0.004 to 0.008 weight percent of an oxidate material selected from the group consisting of an oxidate derived from deoiled macrocrystalline wax having a Neut. No. between and 95, a Sap. No. between 210 and 250, a Neut. No. to Sap. No. ratio between 0.3 and 0.4 and an unsaponifiable content less than 40 percent, and an oxidate derived from a parafiinic lubricating oil and having a Neut. No. between 60 and 70, a Sap. No. between and 165, an SUS viscosity at 210 P. less than 100, a Lovibond V2" cell color rating less than 100, and an unsaponifiable content less than about 55 percent.

23. An improved leaded gasoline as described in claim 22 in which the oxidate material is an oxidate derived by air oxidation of a macrocrystalline Wax having from 25 to 30 carbon atoms, an oil content less than 3 percent and isolated by solvent dewaxing a paraflin base distillate oil.

24. An improved leaded gasoline as described in claim 22 in which the oxidate material is an oxidate derived by air oxidation of a refined paraflinic lubricating oil having an SUS viscosity at 100 F. of between and 180 and a pour point less than 5 F.

References Cited in the file of this patent UNITED STATES PATENTS 1,826,439 Stryker Oct. 6, 1931 2,086,589 Wasson July 13, 1937 2,118,915 Butz et al May 31, 1938 2,155,678 Oosterhout Apr. 25, 1939 2,367,815 Williams Jan. 23, 1945 2,398,281 Bartholomew Apr. 9. 1946 2,654,697 Andress et a1 Oct. 3, 1953 2,667,408 Kleinholtz Jan. 26, 1954 UNITED STATES PATENT OFFICE Certificate of Correction Patent No. 2,965,458 December 20, 1960 Richard L. Sawyer et al.

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

In the grant (only), columns 9, 10, 11 and 12 were inadvertently omitted and should appear as shown below as part of the Letters Patent Table IV ROAD EVALUATION OF INTAKE SYSTEM AND SPARK PLUG OLEANLINESS Intake Intake Spark Intake Intake Spark Mani- Port Plug Manl- Port Plug fold [old Reference fuel 8. 5 D. B 8. 8 8. 5 6. 9 6. 3 Reference fuel connaphthene base ollwar oxidata sddltlve. l0. 9. B 9. 0 0. 3 7. 6 7. 4 Reference fuel-iehloropropyl thlonofobospbaten 8. B 9. 9 & 5 6. 7 5. 0 3. 8 'Irtcresy phosphate-contalnlng premium fuel.- 9. 5 9. 4 7. 9 8. 9 6. l 6. 2

need for a 95 octane fuel during service. It has been postulated that octane requirement increase is attributable partially to engine design and partially to the fuel.

Reduced octane requirement increase as demonstrated in the laboratory for the additive-containing motor fuel of this invention in comparison with the reference fuel by a procedure involving a determination of the initial octane requirement using selected leaded primary reference fuels. In the determination of the initial octane requirement increase, the engine is accelerated at wide open throttle at 700 to 2,000 r.p.m. with a dynamometer preloaded so that the acceleration consumes approximately 12 seconds. The quality of the reference fuel is continually lowered until engine knock is just audible. The octane number of the fuel used when engine knock is just audible is the octane requirement of the engine. After three hours of operation, the accelerations are repeated with a reference fuel two numbers above the initial octane number requirement. Four accelerations with reference fuel are made, and if knock occurs on at least two, it is recorded as an octane requirement increase. If knock only occurs on one acceleration or not at all, the same reference fuel is used at the end of the next three hours; if knock still does not occur on at least two accelerations, the reference fuel two octane numbers lower is used at the end of the succeeding three hours. When knock occurs on at least two accelerations, it is counted and the reference fuel two octane numbers higher is used at the end of the succeeding three hours. After the engine has reached an octane requirement of 96, the reference fuels are used in one octane number increments after each three hours of operation. The conditions for both the octane requirement increase and preignition tests are as follows:

Duration 168 hours.

Cycle 30 seconds at 500 rpm, no

load, and 30 seconds at 1500 r.p.m., 15 B.H.P.

Cooling water inlet 145 F.

Cooling water outlet 160 F.

Crankcase oil Uncontrolled. Transmission oil 250 F. maximum. Static spark setting 2% B.T.C.

In a laboratory test, the additive-containing fuel of this invention gave an octane requirement increase of 10.3 units in the above test, whereas the reference fuel gave an octane requirement increase of 11 units.

PREIGNITION 1 0 of times combustion knock is encountered during a run, that is,

No. of run-onX 100 No. of knocks The ratings of the various fuels in the prcignition tests are shown in Table V.

preignition rating:

Table V PREIGNITION RATING Percent preignition Reference fuel 70 Reference fuel containing naphthene base oil-wax oxidate additive 20 Reference fuel plus trichloropropyl thlonophosphate 16 The foregoing data show the clear superiority of the additive-containing fuel of this invention over the reference fuel. It is noteworthy that the trichloropropyl thionophosphatc-containing fuel is approximately equivalent to the additive-containing fuel of this invention in improving preignition.

The foregoing road tests and laboratory data conclusively demonstrate the improved performance obtained using the additive-containing motor fuel of this invention in a large number of different cars. The improved performance characteristics obtained with the motor fuel containing a light distillate oil and an ester-type oxidate derived from deoilcd paraflin macrocrystalline wax are summarized as follows:

(I) Reduced wear.

(2) Improved valve performance and life. (3) Rust protection.

(4) Reduced spark plug fouling.

(5) Reduced induction system deposits. (6) Improved anti-stalling properties.

(7) Improved preignition characteristics. (8) Higher road octane.

(9) Reduced octane requirement increase.

Although the road test was run employing a light naphthcne base distillate as a component of the additive, laboratory data have indicated that a mixture of estertype wax oxidnte and light parafiin base distillate having an SUS viscosity at 100 F. between 50 and 300 performs excellently as a motor fuel additive. An additive-containing motor fuel was prepared by incorporating in the nfore-dcscribed reference fuel 0.5 percent by volume of a Z-component mixture made by adding 0.057 pound of ester-type wax oxidate used in the road test to a gallon of parafiin base distillate lube oil having an SUS viscosity at 100 F. of about 105. The finished gasoline contained approximately 0.005 weight percent ester-typo oxidate and about 0.6 weight percent paraffin base distillate oil. Another motor fuel was prepared by incorporating in the same reference fuel a 2-component additive made by adding 0.057 pound of ester-type wax oxidate to a white oil obtained by exhaustive refining of a naphthene base distillate oil by H treating and having an SUS viscosity at F. of 100. The 2 fuels were compared with the naphthene base-ester-type oxidate-containing fuel employed in the road tests in the laboratory in the Chevrolet CRC FL2 test. In Table VI, there are shown the merit ratings of these fuels using the previously-described CRC L-4-545 rating system.

Table VI 1.. ENGINE OLEANLINESS The foregoing data show that a parafiin base distillate and a highly refined distillate which has been sulfuric acid treated may be substituted for naphthene base distillate oil in the 2-oomponent additive mixture of this invention.

The foregoing test data showing the superiority of fuel composition containing the additive of the invention wherein the ester-type wax oxidate was a component are common to this specification and that of application Ser. No. 427,660, filed May 4, 1954, and of which this ap plication is a continuation-in-part.

The superior performance of the improved motor fuel of the invention wherein the paraifinic lubricating oil oxidate was the additive component, has also been demonstrated in laboratory bench tests and in high speed road tests. In these tests the data obtained indicated that fuels containing the additive with the parafiinic oil oxidate component were at least equivalent in performance to fuels containing the additive with the estertype wax oxidate component.

The road test conducted to evaluate the parafiinic oil oxidate containing additive consisted of four round-trip runs over the same road course daily in the San Antonio, Texas, area for an accumulation of 750 miles per day and a total mileage of 20,000 miles. Maximum speeds were limited in accordance with legal regulations and good judgment. Speed limits of 60 m.p.h. during the day and 5S m.p.h. at night prevailed on the open road and various limits as low as 30 m.p.h. were maintained in towns along the test route.

In this road test, four 1957 Buick Series 40 (Special) with Dynaflow were used in connection with the testing of the motor fuels of this invention. Two of the cars were run on the base fuel plus the 0.5 wt. percent paraffinic oil oxidate-oontaining additive and the other two cars were run on the base fuel plus 0.5 wt. percent estertype wax oxidate-containing additive for comparison since the excellent performance of this fuel had been well established by extensive road testing and years of customer satisfaction. All four cars used detergent-type motor oil of the heavy duty type meeting Supplement I level requirements and having an SAE grade of 20-20W.

Extensive preparations prior to the actual road testing were made in much the same manner as the preparations, including engine adjustments and inspections, previously made in connection with the road testing of the motor fuel containing the ester-type wax oxidate-lube oil additive of the invention and reported earlier in this specification.

The base fuel comprised mainly light fluid catalytically cracked stock and cataly-tieally reformed gasoline. This base fuel had an AS'I'M research octane rating of 99, contained 2.82 cc. of tetraethyl lead fluid per gallon, had a API gravity of 56.6 and a boiling range between 98 and 366 F. This base fuel also contained minor amounts of conventional additives. These additives included about 1.2 lbs. per 1000 bbl. of N,N'-disalicylidene- 1,2-diaminopropane, a metal deactivator, and about 6 lbs. per1000 bbl. of N,N'-disecondary bu-tyl-p-phenylenediamine, a gum inhibitor.

The motor fuel containing the ester-type wax oxidate component additive was obtained by adding to the base fuel 0.5 percent by volume of the additive comprising 0.8 volume percent of ester-type wax oxidate derived by catalytic oxidation of macroerystalline wax isolated from a lube distillate of SAE 20 grade and having a Neut. No. of 80, a Sap. No. of 230 and an unsaponifiable content of 33 percent, in a naphthene base lube oil having an SUS viscosity of 100' F. of about 100. This fuel composition, which will hereinafter be referred to as motor fuel containing additive A, contained 0.005 wt. percent ester-type wax oxidate and about 0.6 weight percent naphthene base lube oil.

The motor fuel containing the paraflinic oil oxidate Mum's-4 QI'A::U. Brae mam-M 1-! arldina in the. lance fuel 0.5 percent by volume of an additive comprising the same lubricating oil component used in additive A and about 1.125 volume percent of an oxidate prepared by catalytic oxidation of a refined parafiin base lube oil having an SUS viscosity at 100 F. of 144, a API gravity of 31.8 and a pour point of -5 F. This fuel composition, which will hereinafter be referred to as motor fuel containing aditive B, contained 0.0075 wt. percent paraifin oil oxidate and about 0.6 weight percent naphthene base lube oil.

RINGWEAR After completion of the 20,000 mile road test, the compression rings were weighed to the nearest milligram after cleaning with L-4 type cleaning solution and polishing with metal polish. Ring wear was determined by the weight loss of the rings during the road test. In Table VII there is shown the average weight loss of compression rings per car in the 20,000 mile road test with the two specified fuel compositions of the invention.

Table VII COMPRESSION RING WEAR Avg. wt. loss in mg.

Base fuel+additive A 180 Base fuel+additive B This demonstrates that the parafiin oil oxidate-lube oil additive compares very favorably with the excellent wax oxidate-naphthene oil additive of the invention in respect to ring wear.

EXHAUST VALVE PERFORMANCE Evaluation of the exhaust valves by a merit rating system similar to the CRC L-4-545 Test used for evaluating pistons and described in detail on page 401 of the CRC Handbook, 1946 edition, under the heading "Oxidation Characteristics of Heavy Duty Motor Oils, showed a substantial improvement for the improved motor fuel of this invention in the 20,000 mile road test. This merit system involves visual examination of the engine part in question, exhaust valves in this instance, and rating them according to deposits by comparison with standards which have been assigned ratings; a rating of i0 is optimum, and a rating of 0 represents the worst condition. Table II shows the average exhaust valve merit ratings of valves from all cars testing fuels containing all four additives after completion of the 20,000 mile road test.

Table VIII EXHAUST VALVE MERIT RATING Avg. Ex. Avg. Ex. Tulip Stem Base iuel+Additive A 7.2 7.0 Base iueH-Addltive B 7. 2 7.3

Additive B (oil oxidate-l-oil) compares very favorably with the excellent additive A (wax oxidate+oil) with respect to exhaust valve cleanliness as seen in the above table.

FUEL AND LUBRICANT ECONOMY The average mileage obtained for both fuel and oil for the test cars in the 20,000 mile road test is set forth 2,965,458 in the printed specification, column 9, lines 1 to 18, strike out Table IV, and insert the same after in Table IV., in column 8, line 63.

Signed and sealed. this 6th day of June 1961.

Attest: ERNEST W. SWIDER, DAVID L. LADD, Attesting Ofiicer. Commissioner of Patents. 

1. A MOTOR FUEL ADDITIVE COMPRISING FROM 95 TO 99.8 WEIGHT PERCENT LIGHT DISTILLATE MINERAL LUBRICATING OIL FRACTION HAVING AN SUS VISCOSITY AT 100*F. BETWEEN 50 AND 300 AND A CONRADSON CARBON CONTENT BELOW 0.02 PERCENT, AND 0.2 TO 5 WEIGHT PERCENT OF AN OXIDATE MATERIAL SELECTED FROM THE GROUP CONSISTING OF AN OXIDATE DERIVED FROM A DEOILED MACROCRYSTALLINE WAX AND HAVING A NEUT. NO. BETWEEN 60 AND 100, A SAP. NO. ABOVE 170, A NEUT. NO. TO SAP. NO. RATIO BETWEEN 0.25 AND 0.5 AND AN UNSAPONIFIABLE CONTENT LESS THAN 40 PERCENT, AND AN OXIDATE DERIVED FROM A PARAFFINIC LUBRICATING OIL AND HAVING A NEUT. NO. BETWEEN 55 AND 80, A SAP. NO. BETWEEN 100 AND 200, AN SUS VISCOSITY AT 210*F. LESS THAN
 200. A LOVIBOND 1/2" CELL COLOR RATING LESS THAN 200, AND AN UNSAPONIFIABLE CONTENT LESS THAN ABOUT 55 PERCENT. 